Adhesive closure system

ABSTRACT

A touch fastener system, consisting of two interconnectable and detachable touch fastener parts (4), each of which has a plurality of fastening elements (6) projecting from a carrier, which fastening elements (6) can be brought into detachable engagement with each other opposite from each other in a predeterminable connection area, wherein the fastening elements (6) of the one type of a touch fastener part (4) within the connection area receive the fastening elements (20) of the other type between them forming strips (22, 24), is characterized in that one of the touch fastener parts (4) has fastening elements (6) of only one type, which, when engaged within the connection area, are connected to fastening elements (6) of this type and to fastening elements (20) of a further type of the respective other touch fastener part (4).

The invention relates to a touch fastener system having the features inthe preamble of claim 1.

Touch fastener systems are state of the art and freely available in themarket in a variety of forms. In widespread embodiments, the film-shapedcarrier is formed by a polyamide base fabric, from which stems formingthe fastening elements protrude, for example in the form of mushroomheads or hooks formed at the ends of the stems, which fastening elementscan engage with the fastening elements on the other touch fastener partforming a counterpart. In advantageous embodiments, mushroom heads areprovided on both touch fastener parts to be interconnected, whichmushroom heads interlock to form a so-called “hermaphrodite fastener”. Afastener system of this type is available from the applicant under theproduct name Duotec®.

Touch fastener systems of this type are characterized by a high bindingforce, i.e. a high resistance to the mutual peeling of the touchfastener parts from each other, whereas the closing force required toproduce the hooking engagement in contrast is much lower. Theseadvantageous properties are diminished by a lower shear strength, i.e.the force that counteracts displacements of the touch fastener parts,when lateral forces parallel to the film-shaped carrier are applied. Inorder to improve the relation between binding force and shear strength,it is known not to arrange fastening elements in equidistant linear rowsand columns, but in special patterns. For instance, document EP 0 565750 B1 shows a so to speak “chaotic” arrangement of mushroom-head-likefastening elements in sub-areas, wherein the sub-areas of the samepattern arrangement are repeated to form a larger total area. A furthersolution, which is disclosed in document DE102 40 986 B3, provides forthe arrangement of fastening elements along arcs having a sinusoidalcourse. However, the respective improvements in shear strength achievedin this way are not fully sufficient for applications of the touchfastener systems, where occurrence of displacement forces are to beexpected, as is the case, for example, when used to fasten panels orcovers to wall surfaces.

DE10 2012 023 920 A1 discloses a generic touch fastener systemconsisting of two interconnectable and detachable touch fastener parts,each of which has a plurality of fastening elements projecting from acarrier, which fastening elements can be brought into detachableengagement with each other opposite from each other in a predeterminableconnecting area, wherein the fastening elements of the one type of atouch fastener part receive within the connecting area the fasteningelements of the other type between them, forming strips.

With regard to this difficulty, the invention addresses the problem ofproviding a touch fastener system of the genus mentioned at thebeginning, which is characterized by a higher shear strength whilemaintaining a high binding force.

According to the invention, this problem is solved by a touch fastenersystem having the features of claim 1 in its entirety.

According to the characterizing part of claim 1, an essential feature ofthe invention is that one of the touch fastener parts has fasteningelements of the one type which, when engaged within the connecting area,are connected to fastening elements of this type and to fasteningelements of a further type of the respective other touch fastener part.When equipping one of the touch fastener parts with fastening elementsof different types, the combination of the interacting fasteningelements can be laid out such that the engagement of the fasteningelements of the one type with the fastening elements of the same type onthe other touch fastener part results in high binding forces, while atthe same time the engagement of these fastening elements with thefastening elements of the second type on the other touch fastener partresults in a high shear strength. This permits achieving a particularlyfavorable ratio between binding forces and shear strength, so that anextended range of applications can be achieved for the touch fastenersystem according to the invention.

The arrangement can be advantageously made in such a way that thefastening element of the respective one type is formed by a stemprojecting from the assignable carrier, the free end of which stem has amushroom-shaped head, and that the fastening element of the respectiveother type consists of a loop or sling arranged on the assignablecarrier. The engaging mushroom heads of the fastening elements of theone type provide the desired high binding force, whereas the engagementof the mushroom heads of the fastening elements of the first type havingthe loops or slings provides high values of shear strength.

The strips, aligned equally in length and width on the carrier, can beformed in alternating sequence from fastening elements of the one typeand of the other type, wherein the respective strip, viewed transverselyto the longitudinal direction of its carrier, can have a greater lengththan its width in the longitudinal direction of the carrier.

To form a type of fastening clip, the carrier can advantageously form asquare section piece, which carries two strips of fastening elements ofthe one type and one strip of fastening elements of the other type. Allfastening elements of the one type and of the other type can begeometrically identical in their respective typ.

In advantageous embodiments, the fastening elements of the one type ofthe one touch fastener part abut on a common end plane in terms of theiraxial extension from the upper side of their carrier.

The fastening elements of the second type of the other touch fastenerpart end, starting from the upper side of their carrier, at apredeterminable distance below a common end plane, on which the freeends of the fastening elements of the one type of the other touchfastener part abut.

Advantageously, both the one and the other end plane extend in parallelto the respective assigned upper surface of the carrier and have thesame perpendicular distance from their upper carrier surface.

In advantageous embodiments, the fastening elements of the one typestand uniformly in rows and columns on their carrier and are equidistantfrom each other such that the mushroom-shaped heads of the fasteningelements of the one type of a touch fastener part engage between thefastening elements of the one type of the other touch fastener part andhook together with their mushroom-shaped heads by forming the detachablefastening.

The arrangement can be advantageously made in such a way that thefastening elements of the one type have an arc-shaped, in particularsinusoidal, set-up pattern, at least in relation to a strip.

Alternatively, the fastening elements of the one type can have at leastone chaotic set-up pattern, at least in relation to one strip.

In particularly advantageous embodiments, the fastening elements of theone type are formed from a fabric, which has loops that form stem partsafter having been sliced-through, the free ends of which stem parts,when heated, form the mushroom-like heads under the internal stress oftheir plastic material, wherein the loop or sling shape of the fabric isretained to form the fastening elements of the other type.

Advantageously, the fabric forming the fastening elements is coated, inparticular with a polyurethane coating.

The carrier, which is provided with the fastening elements of only theone type, can also consist of an injection-molded or extruded plasticsection.

In an alternative embodiment, the respective carrier, preferably thecarrier having the fastening elements of the one type and of the secondtype, can be formed multi-part and can have an injection-molded orextruded plastic section as a base carrier and the fabric forming therespective fastening elements, which fabric is glued to the basecarrier.

Preferably the respective fabric is connected to the plastic section bya liquid-crosslinking polyurethane adhesive.

The invention is explained in detail with reference to the drawingattached below.

In the Figures:

FIGS. 1a and 1b show a schematically simplified and enlargedrepresentation, not to scale, of a first and a second touch fastenerpart of the usual type for forming a touch fastener system according tothe state of the art;

FIG. 1c shows a simplified representation corresponding to FIGS. 1a and1b of the touch fastener system according to the state of the art formedfrom the touch fastener parts;

FIGS. 2 and 3 show a sketchy and simplified representation not to scaleof a surface area of two further touch fastener parts according to thestate of the art;

FIGS. 4a and 4b show a representation corresponding to FIGS. 1a and 1bof a first and a second touch fastener part for forming a touch fastenersystem according to an embodiment of the invention;

FIG. 4c shows a representation corresponding to FIGS. 4a and 4b of thetouch fastener system formed from the touch fastener parts according toan embodiment of the invention;

FIG. 5 shows a perspective oblique view, viewed towards the top, of aschematically simplified representation, not to scale, of the touchfastener part of FIG. 4b ; and

FIG. 6 shows a representation corresponding to FIG. 4b of a modifiedversion of the second touch fastener part.

FIGS. 1a and 1b each show a state of the art touch fastener part 2,which form the active components of a conventional touch fastener systemand which are provided with the same type of fastening elements 6, whichare only partially numbered in the figures. The fastening elements 6 areformed by mushroom heads 8, only part of which are numbered in thefigures and which are located at the ends of the stems 10, whichprotrude from a flat carrier 12. When the fastening elements 6 engagewith each other, touch fastener parts 2 of this type form a so-calledmushroom-in-mushroom fastener of a state-of-the-art touch fastenersystem, as shown in FIG. 1c . Touch fastener parts 2 of this type arecommercially available and can be obtained from the applicant under theproduct name Duotec®. A base fabric of polyamide having polypropylenestems 10 on which the mushroom heads 8 are formed by thermal processingforms the carrier 12 of the touch fastener parts 2. The carrier 12having the fastening elements 6 can also consist of an injection-moldedor extruded plastic section.

Touch fastener systems of this known type are characterized by a highbinding force, which counteracts the disengagement by peeling the touchfastener parts 2 off each other. These known touch fastener systems alsorequire a comparatively low closing force to produce the engagement andare therefore easy and safe to handle. However, the level of shearstrength, i.e. the resistance to relative sliding motions of the touchfastener parts 2, leaves something to be desired for some applications,for instance when using the touch fastener system as the only attachmentmeans for mounting panels or covers on wall surfaces. FIG. 2 illustratesa state-of-the-art solution, where, in an effort to achieve a highershear strength, touch fastener elements 6 are arranged at the commonarea of a touch fastener part 14 not in regular rows and columns but ina special pattern, as in the chaotic arrangement shown in FIG. 2, or inan arrangement as shown in the document EP 0 565 750 B1 alreadymentioned. FIG. 3 illustrates a further known approach for increasingthe shear strength. As shown, at the connection area of the touchfastener part 16 fastening elements 6, having mushroom heads 8, of thetype shown in FIGS. 1a to 1c are arranged along arc lines 18, which areformed in the manner of sine waves. Such an arrangement can be realized,if the fastening elements 6 are produced by heat treatment of threads ofa base fabric in the manner shown in the already mentioned documentDE102 40 986 B3. The base fabric may be provided with a polyurethanecoating. FIGS. 4a, 4b and 4c show an embodiment of the touch fastenersystem according to the invention. It is made of different types oftouch fastener parts, one of which is formed by the touch fastener part2 of a known type as shown in FIGS. 1a and 1b , wherein Duotec® 50 isprovided in the embodiment. On the carrier 12 of the other touchfastener part 4, serving as a counterpart, there are fastening elementsof a first and of a second type in the connection area, wherein thefastening elements of the first type correspond to the fasteningelements 6 of the touch fastener part 2, whereas the fastening elementsof the second type are formed by loops 20. As FIG. 5 shows, in which thesecond touch fastener part 4 is shown in top view, the fasteningelements 6 of the first type are arranged on the carrier 12 in twostrips 22, between which the loop-like fastening elements 20 extend in athird strip 24. In this example, the strips 22 are each formed by astrip of Duotec® 50, and the middle strip 24 is formed by a strip in theform of a fleece material, such as that distributed commercially by theapplicant under the product name Klettostar®. The strips 22 and 24 areeach rectangular and each have the same length and width, wherein thelength is greater than the width of the strips 22, 24. As the comparisonof FIGS. 4a, 4b and 4c yields, the heads 8 of the fastening elements 6of the first type end, both for the first touch fastener part 2 and forthe second touch fastener part 4, each in common end planes 26 and 27(FIGS. 4a, 4b ), spaced apart from the carrier 12, whereas the fasteningelements 20 of the second type end slightly below the plane 27 of thesecond touch fastener part 4.

Experiments, in which a known touch fastener system, in which both touchfastener parts are formed by Duotec® 50, was compared to the systemaccording to the invention, in which the first touch fastener part 2consists of Duotec® 50 and the second touch fastener part 4 consists ofthe strip arrangement shown in FIG. 5, where two strips 22 are made ofDuotec® 50 and one strip 24 is made of Klettostar®, have shown that thelatter system provides an approximately 33% higher shear strengthagainst relative displacements in parallel to the longitudinal directionof the strips 22, 24 and a more than 36% higher shear strength againstdisplacements transverse to the longitudinal direction, compared to theknown system having the same kind of touch fastener parts made ofDuotec® 50.

As shown in FIG. 6 using the touch fastener part 2, which has thefastening elements of the one type 6 and the fastening elements 20 ofthe second type, by way of example, the carrier 12 can be formedmulti-part. As shown, a base carrier made of an injection-molded orextruded plastic section 30 is provided, to which the respective fabric32, which forms the fastening elements 6, 20, is glued. Preferably thefabric 32 has a polyurethane coating on the side facing the basecarrier, wherein a moisture-crosslinking polyurethane adhesive 34 may beprovided as the adhesive for forming the connection to the plasticsection 30.

1. A touch fastener system, consisting of two interconnectable anddetachable touch fastener parts (2, 4), each of which has a plurality offastening elements (6) projecting from a carrier (12), which fasteningelements (6) can be brought into detachable engagement with each otheropposite from each other in a predeterminable connection area, whereinthe fastening elements (6) of the one type of a touch fastener part (4)within the connection area receive the fastening elements (20) of theother type between them forming strips (22, 24), characterized in thatone (2) of the touch fastener parts (2, 4) has fastening elements (6) ofonly one type, which, when engaged within the connection area, areconnected to fastening elements (6) of this type and to fasteningelements (20) of a further type of the respective other touch fastenerpart (4).
 2. The touch fastener system according to claim 1,characterized in that the fastening element (2) of the respective onetype is formed by a stem (10) projecting from an assignable carrier(12), the free end of which stem (10) has a mushroom-shaped head (8),and that the fastening element (20) of the respective other typeconsists of a loop or sling arranged on the assignable carrier (12). 3.The touch fastener system according to claim 1, characterized in thatthe strips (22, 24), aligned equally in length and width on the carrier(12), are formed in alternating sequence from fastening elements of theone (6) and the other type (20).
 4. The touch fastener system accordingto claim 1, characterized in that the respective strip (22, 24), viewedtransversely to the longitudinal direction of its carrier (12), has agreater length than its width in the longitudinal direction of thiscarrier (12).
 5. The touch fastener system according to claim 1,characterized in that the carrier (12) forms a square surface piece,which carries two strips (22) of fastening elements (6) of the one typeand one strip (24) of fastening elements (20) of the other type.
 6. Thetouch fastener system according to claim 1, characterized in that allfastening elements (6, 20) of the one type and of the other type aregeometrically identical in their respective typ.
 7. The touch fastenersystem according to claim 1, characterized in that the fasteningelements (6) of the one type of the one touch fastener part (2) abut ona common end plane (26) in terms of their axial extension from the upperside of their carrier (12).
 8. The touch fastener system according toclaim 1, characterized in that the fastening elements (20) of the secondtype of the other touch fastener part (4) end, starting from the upperside of their carrier (12), at a predeterminable distance below a commonend plane (27), on which the free ends of the fastening elements (6) ofthe one type of the other touch fastener part (4) abut.
 9. The touchfastener system according to claim 1, characterized in that both the oneand the other end plane (26) extend in parallel to the respectiveassigned upper surface of the carrier and have the same perpendiculardistance from their upper carrier surface.
 10. The touch fastener systemaccording to claim 1, characterized in that the fastening elements (6)of the one type stand uniformly in rows and columns on their carrier(12) and are equidistant from each other such that the mushroom-shapedheads (8) of the fastening elements (6) of the one type of a touchfastener part (2) engage between the fastening elements (6) of the onetype of the other tough fastener part (4) and hook together with theirmushroom-shaped heads (8) by forming the detachable fastening.
 11. Thetouch fastener system according to claim 1, characterized in that thefastening elements (6) of the one type have an arc-shaped, in particularsinusoidal, set-up pattern (18), at least in relation to a strip (22).12. The touch fastener system according to claim 1, characterized inthat the fastening elements (6) of the one type have at least onechaotic set-up pattern, at least in relation to a strip (22).
 13. Thetouch fastener system according to claim 1, characterized in that thefastening elements (6) of the one type are formed from a fabric (12),which has loops that form stem parts (10) after having beensliced-through, the free ends of which stem parts (10), when heated,form the mushroom-like heads (8) under the internal stress of theirplastic material, and in that the loop or sling shape of the fabric isretained to form the fastening elements (20) of the other type.
 14. Thetouch fastener system according to claim 1, characterized in that thefabric (12) forming the fastening elements (6, 20) is coated, inparticular is provided with a polyurethane coating.
 15. The touchfastener system according to claim 1, characterized in that the carrier(12) having the fastening elements (6) of only the one type consists ofan injection-molded or extruded plastic section.
 16. The touch fastenersystem according to claim 1, characterized in that the respectivecarrier (12), preferably the carrier (12) comprising the fasteningelements of the one type (6) and of the second type (20), is formedmulti-part and comprises an injection-molded or extruded plastic section(30) as a base carrier, to which the fabric (32) forming the respectivefastening elements (6, 20) is glued.
 17. The touch fastener systemaccording to claim 1, characterized in that the respective fabric (32)forming the fastening elements (6, 20) is connected to the plasticsection (30) by a liquid-crosslinking polyurethane adhesive (34).